(1) Field of the Invention
The invention relates to a screw compressor for compressing a working fluid to an extremely high discharge pressure featuring two rotors, a male rotor having essentially convex-shaped lobe flanks with at least four lobes and a female rotor with the male rotor having a drive-shaft end, and both rotors are enclosed in a housing featuring at least an inlet port for passing of the working fluid into the lobes of the rotor pair and at least an outlet port for forcing the gas out of the interlobe spaces of the rotor pair due to rotation of the rotors.
(2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
The profile sections of the rotors have shaft shoulders enclosed in radial bearings. There is one bearing per each side of the profile section. The resulting axial forces are being supported by axial bearings.
The profile section of the rotors is extremely short. The axial length of the profile section of the rotor pair corresponds to approx. 1,4 the value of the axial lobe pitch which corresponds to the axial distance between two lobe-flank points of neighbouring lobe flanks. Known compressors have several housing sections accommodating the bearings of the rotors. These housing sections are connected with each other by suitable means after having been fixed at reference points. (U.S. Pat. No. 4,042,310, U.S. Pat. No. 4,004,864, U.S. Pat. No. 4,084,405, U.S. Pat. No. 4,455,131, U.S. Pat. No. 4,597,726, U.S. Pat. No. 4,748,831)
This configuration leads to impermissible inclined positions of the bearings, if there are rotors with very short profile sections as the axial distance between the radial bearings arranged on both sides of the rotors is very short.
This has an impermissible impact on both the service life and load-carrying capacity of the bearings. The essence of the invention is that the housing section, which encloses the profile section of the rotors, is cup-shaped and that the adjacent outer diameters of the parts arranged in this housing section decrease when going from the open to the closed end of the housing section and that all the parts can be mounted from one side of the housing.